High-Efficiency, High-Power Density and Wide-Range Power Supply Design Based on GaN HEMT

Abstract

To enrich the functions of the flyback converter, enable it to achieve high-efficiency and high-power density, and at the same time have more flexibility and apply to more occasions, in this paper, GaN HEMT and transient voltage suppressor (TVS) are used to design a high-efficiency, high-power density, wide-input and wide-output power supply based on quasi-resonant flyback converter (QRFC). To solve the problem that the gate drive voltage requirement of GaN HEMT is different from that of Si-MOSFET, a corresponding drive level conversion circuit is designed. In order to solve the problem of the power supply of the controller when the output is in a wide range, the power supply circuit of the wide-range controller is studied. In view of the cumbersome design and calculation of the traditional resistor capacitor diode (RCD) clamping circuit and the large loss of energy, TVS is used to redesign the clamping circuit to avoid the calculation and selection problems of the clamping capacitor C and the discharge resistance R. The loss is smaller and the design is more convenient. Aiming at the difficulty of designing transformer core and primary inductance when the switching frequency changes, a switching frequency interval estimation method based on the constraints of switching loss and output filter capacitor conditions is proposed to simplify the design of the transformer. The experimental results show that the high-efficiency, high-power density and wide-range power supply designed in this paper can achieve input 90-265VACrms, rated 220VACrms, output 5-15V wide-range adjustable, full load up to 75W, power density up to 17.44 W/inch³, and the highest efficiency can reach 92.6%, and the output ripple voltage is less than 50mV.